I have a hard plastic pretty basic black mast shim that works but is not a snug fit for my x9 160 boom a few years old. Yesterday I got my mast stuck (x9 430 rdm similar age) and had to do the two boom thing, but mine kept slipping under that sort of load, but doesn't slip windsurfing. Eventually got it to stay after mucking around for too long into beer time.
I used to have a rubber one which was a softer plastic and slightly fatter and not sure of brand, it worked great but split after a season. Any suggestions on a good one that makes a more snug fit with the x9?

NP one is rubber ..... I imagine a better fit too, being NP?

Thanks, probably answered my question right there Mark. I thought the NP was the hard plastic but was probably the black rubber one that split. I haven't seen them for a while, only the plastic. I will see if they can order me some in at the local shop.

The mast will come apart if you immerse it in water, salt will do, and gentle work it apart. No great leverage or pressure needed.

The NP boom has a shim that clips into to the boom jaws, you can buy them as an accessory . I like this as it makes it easier to fit the boom without having to fiddle with a shim on the mast first.

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cameronil said..
Thanks, probably answered my question right there Mark. I thought the NP was the hard plastic but was probably the black rubber one that split. I haven't seen them for a while, only the plastic. I will see if they can order me some in at the local shop.

Mine are 10yrs old so maybe a material change

The no-limitz one that is supplied with ezzy masts is a great shim and never slips but may not be big enough the NP (as in, it is much shorter than the NP one)

actually with modern booms, RDM shims are NOT necessary
one can just adjust the rope on the clamp
and yes, i have busted a shim and resorted to adjusting boom
but went back to rubber RDM shim and lazy way out
actually put thin plastic shim on SDM too for protection on the mast

Cheap Billows one is rubber and works a treat, 4 years on and still semi-soft and rubbery.
As a bonus it serves as a under sail footer anti board strike helper, teamed up with pulley wear reducer fish tank tuber duber.
Deluxe mods these ones

Thanks everyone for replies and the PM. Some good ideas and will try the immersed in salt water approach next time the mast is stuck, though I tape them normally so rarely happens.
I might have found a np rubber shim to try so I think it will be better than the plastic.